A review of studies warns of the carcinogenic potential of nicotine-containing e-cigarettes

I have been publishing papers on this subject (e-cigarettes) since 2009, and I have always said that this link between e-cigarettes and carcinogenic effects was a possibility that would take time to prove, given that an average of 15 to 20 years of use is needed to demonstrate it.

In my opinion, I believe the study is a high-quality systematic review (I am not an epidemiologist to judge it more precisely) and that it provides very solid data to begin discussing vaping and cancer. It describes the pyrolysis processes through which carcinogens are generated by the modification of flavorings and nicotine, outlines studies demonstrating genetic alterations, and presents animal studies (mice) that have already observed carcinogenic effects on the lungs and urinary bladder. It reveals that there are already several studies linking e-cigarettes to oral cancer and presents the first studies on lung cancer. Authors linked to the industry have often claimed that the toxic content is much lower, but they omit the fact that a regular user of these products may take more than 70,000 puffs per year and that there is no safe threshold for Group A carcinogens such as heavy metals, nitrosamines, and others. Therefore, the conclusions are entirely plausible.

Regarding the implications, it is clear that all available evidence on their short-term respiratory and cardiovascular effects and long-term carcinogenic effects should lead to regulation that is identical to the strict regulations in place for tobacco and traditional cigarettes; there is no justification for softer or more permissive regulation. Likewise, the general public—and particularly young people—must be informed of the risks of these products, which, according to the most recent ESTUDES survey, have been consumed by 26% of schoolchildren aged 14 to 18 in Spain. In any case, the precautionary principle should be sufficient to strengthen these regulations.

Regarding the limitations, it is clear that more clinical case studies are needed in which this association has been observed, and to examine what happens with bladder cancer and other cancers; however, everything indicates that no matter how many studies are conducted, this association will not be ruled out—rather the opposite. There is a study that found a 2.2-fold increased risk of cancer in human e-cig users compared to non-users and non-smokers. The authors were forced to retract their findings by the journal after the article was published, for reasons unknown to us. What I mean is that the industry does everything in its power to discredit any scientists who publish this type of article that threatens its lucrative business, and that must be taken into account.

Regarding the press release, I believe its final sentence accurately reflects the message.

Over the past two decades, the use of e-cigarettes has become increasingly widespread in our society, fueled by nicotine’s addictive properties, the use of flavors and designs that are particularly appealing to teenagers and young adults, and information that portrays these devices as if they merely emitted water vapor. The growing body of studies on the health effects of e-cigarette use—which were scarce when these products first hit the market—leaves no doubt about the harm caused by nicotine addiction in adolescence and the damage these devices inflict on respiratory and cardiovascular health.

It is still difficult to provide epidemiological data on the impact of e-cigarette use on cancer incidence and mortality because, as with other causal factors of this disease such as tobacco use, it is likely to take decades from the start of exposure until a significant number of cases begin to be diagnosed. However, the comprehensive review recently published in the journal Carcinogenesis provides data from numerous studies indicating that exposure to aerosols from nicotine-containing e-cigarettes is associated with some of the key features of carcinogenesis, such as DNA damage, oxidative stress, and epigenetic changes, which contribute to an increased risk of oral cavity cancer, lung cancer, and other forms of cancer among people who use these devices, even if they have not been users of conventional tobacco products.

According to the available scientific evidence, it is not appropriate to propose the use of e-cigarettes as a safe and effective strategy to reduce the risks associated with tobacco use, and it is necessary to adopt new measures to prevent young people and adolescents from taking up their use, by better regulating their promotion and marketing, limiting the use of flavors and designs that make them more appealing, preventing the sale of disposable devices, and subjecting them to a tax regime commensurate with their negative impact on public health, as has been called for by the National Committee for the Prevention of Tobacco Use and other scientific and health organizations